Popularly known vehicles (conventional vehicles), including automobiles, rely solely on gasoline, diesel, or like engines (internal combustion engines) for travel driving force. Recently, environmental-friendly vehicles, such as hybrid vehicles, electric vehicles (EVs), and fuel cell vehicles, have been developed and put into commercial use.
Among the latter vehicles, the hybrid vehicle is provided with an engine and an electric motor (e.g., motor generator or motor) that operates on the electric power either generated from the engine output or stored in a battery (electric storage device). The hybrid vehicle is capable of traveling by using either the engine or the electric motor or both as a driving force source(s).
Hybrid vehicles have a power switch for turning on/off the hybrid system (driving force source). For example, manually operating the power switch with the brake pedal being depressed by the driver starts the hybrid system. Meanwhile, manually operating the power switch while the vehicle is traveling stops the hybrid system.
Patent Document 1 listed below describes technology related to the starting/stopping of the hybrid system in a hybrid vehicle. According to the technology, if the vehicle startup/stop switch is shifted to an engine stop position (Off position, Ready-Off, etc.) while the vehicle is traveling at high speed, the battery is protected by prohibiting the engine from stopping so that the battery discharge does not exceed a maximum discharge limit.